Robotic or autonomous vehicles (sometimes referred to as mobile robotic platforms) generally have a robotic control system that controls the operational systems of the vehicle. In a vehicle that is limited to a transportation function, the operational systems may include steering, braking, transmission, and throttle systems. In October 2005, five autonomous vehicles (of twenty-three finalist vehicles) successfully completed the “Grand Challenge” of the United States Defense Advanced Research Projects Administration (DARPA), a competition requiring fully robotic vehicles to traverse a course covering more than one hundred miles. These vehicles were outfitted with robotic control systems in which a bank of computers controlled all of the operational systems of the vehicle, such as the steering, braking, transmission, and throttle, subject to autonomous decisions made by programs on board the vehicle in response to sensor input, without human intervention on the course itself.
Such autonomous vehicles generally have a centralized robotic control system for control of the operational systems of the vehicle. A typical configuration is a standard office rack mount with several 1U or 2U “blade server” configuration personal computers (three finishing vehicles had six or more of these), and/or workstation class (Itanium, Xeon) servers. Many such vehicles include DC to household AC power conversion, and then plug in the controlling computers (as if in an office environment). Other power supplies are specific or dedicated to the sensor or actuator. Separate diesel generators are were used to generate onboard power for the computer banks Actuator control and amplification/driving is typically handled by separate motor controllers and amplifiers placed close to their actuated system. These centralized robotic control systems are generally bulky and take up a fair amount of space in the vehicle. For example, some of the vehicles had no passenger compartment at all. Space savings is an issue for autonomous vehicles in general, but especially those that can also be used as manned vehicles. In combination manned/autonomous vehicles it is desirable not to take up space used for persons or payload. In high-tolerance, extreme environment vehicles such as military vehicles, available space is at a premium, there being little weight or space to spare.
Some military vehicles have been adapted for autonomous operation. In the U.S., some tanks, personnel carriers (e.g., Stryker) vehicles, and other vehicles have been adapted for autonomous capability. Generally, these are to be used in a manned mode as well. However, these programs are in some ways similar to the Grand Challenge vehicles, at least because they typically result in a large central processing box and a set of power supply, sensor control, motor control, and communications packages that are each hardened and that each affects payload, cargo, or passenger compartments.
A brief catalog of some of the problems associated with the approach taken in almost all of these vehicles includes:
1) Every significant addition of literally any kind of resource—sensor, actuator, compute, or communications, among others—requires significant redesign: providing appropriate power or actuation, routing power to the resource, providing appropriate communication channels, routing communication lines, housing and mounting, heat budget, electromagnetic noise, providing computation or processing to control the resource.
2) Every solution is purpose built for the vehicle adapted, and typically cannot be used on other vehicles (except of similar configuration). All of power, network communications, actuator control are provided ad hoc. No vehicle-wide network is established for any of these.
3) As noted above, passenger and/or payload areas are usually compromised, unless the vehicle is quite large. Even if passenger or payload areas remain useful, they are not useful for long-term use, in view of the exposed wiring, exposed heat sinks, or exposed electronics in the passenger or payload compartments.
4) None consider the problems of survivability or depot-level maintenance (important for high-tolerance, extreme environment vehicles managed in fleets such as emergency or military vehicles).
The Standard Teleoperation System (STS), Standard Robotics System (SRS), or Common Robotics System (Omnitech Robotics International, Englewood, Colo.) were attempts to provide a kit adaptable to a wide range of vehicles for teleoperation. The STS, SRS, or CRS are robust packaging for a wide variety of functional units. For example, each of a vehicle control unit, power system unit, system input/output unit, mobile radio unit, video multiplexer unit, and numerous other system elements is a separately packaged unit that must be connected to the others via CAN bus or RS-232 serial connections. One element, a 17 kilogram, 8 liter “high integration actuator”, includes a linear actuator (motor) as well as position and feedback sensors; a power amplifier; a digital servo processor, and a microcontroller with a CAN interface. The processor and microcontroller are used to control the motor bound in the package, and are not reconfigurable or available to different or other control outside motors or sensors. This unit is essentially an integrated motor package, a so-called “smart actuator”.
While the Omnitech's Standard Robotics System has been adapted to a wide range of vehicles, including tractors, forklifts, earthmovers, mine clearing tanks, this system has several shortcomings for autonomous/manual use. It is slightly more integrated than the adapted vehicles discussed above, but only when using its own actuators. It lacks any capability for high-bandwidth communications necessary for autonomous use (i.e., to carry interpretable and interpreted sensor data to supervisory robotics control), and were such added, even more bulk would be added. Again, were such added, even more bulk would be added. No component, including the vehicle control unit, includes sufficient processing power for autonomous behaviors (e.g., usually 500-1000 MIPS, although less is possible with less autonomy). Lacking the capability for autonomous control, it inherently lacks the ability for autonomous safety management (for example, partial teleoperation, in which, for example, obstacle avoidance behavior can override operator control). It is restricted to its own actuator suite. A separate power supply is part of the system, but this may not be suitable for laser scanners or radios, which (among other components) are sensitive to power quality and to EM noise.